The invention relates to a pressure sensor comprising a diaphragm coupled to an optical system which couples light emitted by a transmitting light guide into two receiving light guides depending on the deflection of the diaphragm.
In the German Patent application No. 28 49 186 an optical measuring instrument with a pressure sensor is disclosed which comprises a diaphragm arranged in front of the end faces of the two receiving light guides. In the case of pressure variation the position of the diaphragm relative to the end faces of the receiving light guides changes and depending on the pressure the light emitted by a transmitting light guide is divided between the two receiving light guides. However, the diaphragm couples only a fraction of the emitted light into the receiving light guides. Therefore, the known arrangement requires the use of a sensitive measuring circuit.